For example, Patent Literature 1 discloses a navigation apparatus, which is mounted in a vehicle (referred to as a host vehicle) and sets in map data a polygon that encloses a region where an urban map is present. The urban map is enabled to be displayed when the location (host vehicle location) of the host vehicle is present inside the polygon region; in contrast, the urban map is disabled from being displayed when the host vehicle location is present outside the polygon region. Such an urban map can be referred to also as street directory and includes buildings and sites facing streets as constituent elements.